JPH0416333Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a switch for detecting that a predetermined acceleration is applied to a vehicle in order to activate a safety device in the event of a vehicle collision.

<Prior art> The injuries sustained by occupants during vehicle collisions include the primary impact caused by collision with road structures or other vehicles, as well as secondary damage sustained by occupants caused by collision with structures inside the vehicle. This may be caused by a shock. In order to prevent this secondary collision, an air bag device is used to restrain the forward movement of the occupant, in which a bag that instantly expands with gas pressure is interposed between the occupant and the obstacle. Various occupant restraint devices have been proposed, such as seatbelt preloader devices, which increase the restraining force on the occupant by rapidly retracting the end portion of the seat belt during a collision.

On the other hand, as a starting means for operating these occupant restraint systems, an inertia weight provided so as to be movable along a predetermined axis is always elastically held at a predetermined position by the restoring force of a spring means. A switch is known in which the contact point is closed by the displacement of the inertia weight due to the effect of deceleration at the time of a collision, and the above-mentioned occupant restraint device is activated by the electric signal at this time.

<Problems to be solved by the invention> By the way, the above-mentioned switch must be able to accurately judge the impact specific to a collision and operate, and in particular, it must be able to adjust the displacement of the inertia weight to a predetermined deceleration. The spring means for alignment must always be operating properly. However, it is difficult to test the normal operation of this switch due to the special circumstances in which it is used, and extremely high reliability over a long period of time is required. Therefore, it is preferable to configure the spring means so that breakage due to fatigue or the like can be detected early and appropriate measures can be taken.

Based on this viewpoint, the main purpose of the present invention is to provide an acceleration detection switch that can easily monitor the state of the spring means that elastically supports the sensor weight of the acceleration detection switch so that it can be displaced in the axial direction. be.

<Means for Solving the Problems> According to the present invention, the sensor weight is floatingly supported via spring means so as to be able to be displaced along a predetermined axis by inertia. An acceleration detection switch configured to generate a signal when displaced in an axial direction by the action of a predetermined acceleration, wherein means for detecting conduction of the spring means is connected to both ends of the spring means. This is achieved by providing an acceleration detection switch characterized by:

<Function> In this way, if the spring means supporting the sensor weight breaks due to fatigue or the like, the conduction state at both ends of the spring changes, so that a defect in the spring means can be immediately discovered.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 shows an acceleration detection switch constructed based on the present invention. The casing 1 of the acceleration detection switch includes a rear half 1a formed by injection molding or the like of synthetic resin and having a generally bottomed cylindrical shape, and a front half 1 that airtightly closes the opening of the rear half 1a.
The two halves 1a and 1b are integrally joined with a spring member 2 interposed between their opposing surfaces.

A sensor weight 4 having a cylindrical shape and having a predetermined inertial mass is fixed to the center of the spring member 2 by brazing or the like.

At the axial end of the sensor weight 4 on the side fixed to the spring member 2, there is a protrusion 5 along the axial direction.
A guide rod 6 that protrudes through the center of the spring member 2 and has a reduced diameter is formed at the opposite axial end. This guide rod 6 is
Guide hole 7 drilled in the center of the bottom wall of the rear half body 1a
The sensor weight 4 is loosely fitted in the sensor weight 4, and cooperates with the spring member 2 to define the moving direction of the sensor weight 4. In this way, the sensor weight 4 is made movable only in the axial direction while receiving the elastic urging force from the spring member 2, and is usually elastically supported at a position corresponding to the restoring force of the spring member 2. .

A circular plate 11 made of a metal plate is fixed to the base of the guide rod 6 relative to the sensor weight 4 by brazing or the like. A protrusion 11a is provided on the peripheral edge of the disc 11 so as to protrude over the entire circumference toward the bottom wall of the rear half 1a.

A backup plate 12 is insert-molded into the rear half 1a so as to cover the entire inner surface of the bottom wall thereof. Backup plate 12
The retainer plate 14 is made of a relatively rigid material and has a slightly smaller diameter than the disk 11 described above.
is fixed by spot welding or the like at a location not shown. In addition, the retainer plate 14
A suction plate 13 made of a soft material such as synthetic rubber and having a slightly larger diameter than the disk 11 is held between the suction plate 13 and the backup plate 12, with only its peripheral edge 13a exposed. Here, the disc 11 is adapted to come into close contact with the retainer plate 14, and the protrusion 11a is formed on the peripheral edge 13 of the suction plate 13.
It is designed so that it can be brought into close contact with a.

A pair of set screws 19 are provided on the inner surface of the front half body 1b at positions facing each other at equal distances from the center.
a and 19b are screwed together, and this set screw 19
The distal ends of the spiral arms 25 and 26 are adapted to come into contact with the proximal ends of the spiral arms 25 and 26 at appropriate locations. By screwing the push screws 19a and 19b forward and backward, the initial deflection amount of the spring member 2 consisting of spiral arms 25 and 26 (to be described later) changes, thereby changing the elastic force of the spring member 2 against the sensor weight 4. do.

A terminal plate 20 is provided at the center of the front half body 1b.
is insert molded. The terminal plate 20 is bent into an approximately L-shape, and includes a terminal portion 20a extending along the axial direction and a retainer portion 20 perpendicular to the axial direction.
b, and the retainer part 20b is composed of the front half body 1
It is held on both sides in an opening 17 opened at the center of b. A hole 21 into which the protrusion 5 of the sensor weight 4 can be loosely fitted is provided in the retainer portion 20b.
At the same time, a lead piece 22 is fixed so as to close this hole 21 from the outer surface side of the front half body 1b. This lead piece 22 is configured to be able to freely tilt toward the outside of the central portion 17 using a fixing point 22a to the retainer portion 20b as a fulcrum, and is generally in close contact with the retainer portion 20b due to its elasticity.
These terminal plates 20 and lead pieces 22
This constitutes one electrode of the acceleration detection switch.

The opening 17 is filled with a foam material 24 having relatively low elasticity. As a result, sensor weight 4
When the protrusion 5 hits the reed piece 22, the elastic force of the reed piece 22 itself prevents the sensor weight 4 from being repelled.

As shown in FIG. 2, the spring member 2 has a pair of spiral arms 25 and 26 formed by providing a spiral cut outward from the center of a circular phosphor bronze plate. , its outer peripheral portion is fixed to the casing 1. At the bases of the spiral arms 25 and 26, tongue pieces 25a and 26a, which respectively protrude radially outward from the casing 1, are provided at opposite positions. The tongue piece 25a, together with the spring member 2 and the protrusion 5 of the sensor weight 4,
This constitutes the other electrode of the acceleration switch. Further, the outer peripheral part of the spring member 2 is divided by a pair of notches 25b and 26b provided at mutually opposite positions, and both spiral arms 25 and 26 are
The sensor weights 4 are electrically connected to each other only through the fixed center portion.

A monitor circuit (not shown) is provided between the tongues 25a and 26a, and the spiral arms 25 and 2
6 is detected and an abnormality is displayed externally. As a result, when at least one of the spiral arms 25 and 26 breaks due to fatigue or the like, the conduction situation between the tongue pieces 25a and 26a changes, and it becomes possible to immediately notify that a problem has occurred in the spring member 2. ing.

Next, the operation of the above embodiment will be explained.

Normally, the sensor weight 4 is floatingly supported by the biasing force of the spring member 2, and at the same time, the disk 11 is in close contact with the retainer plate 14, and the protrusion 11a is in close contact with the peripheral edge 13a of the suction plate 13.

Here, when deceleration acts on the vehicle, the casing 1 tries to stop together with the vehicle, but the sensor weight 4, which is elastically supported by the casing 1 via the spring member 2, stops the vehicle due to its inertia. Attempt to move in the forward direction. At this time, since the disc 11 is in close contact with the retainer plate 14 and the protrusion 11a is in close contact with the peripheral edge 13a of the suction plate 13, negative pressure acts between the disc 11 and the suction plate 13. It acts as a resistance that prevents the sensor weight 4 from moving. When a sufficiently large and long deceleration is applied, the disc 11 moves to the retainer plate 14.
Then, the protrusion 11a separates from the peripheral edge 13a. Then, the sensor weight 4 moves based on the sensitivity characteristics determined by the elastic resistance given by the spring member 2 and the fluid resistance given by the movement of the disk 11 in the air, and the protrusion 5 of the sensor weight 4 moves as a lead. It is displaced until it hits the piece 22. As a result, the tongue piece 25a and the terminal portion 2
Electrical conduction occurs between the electrodes 0a and 0a, and the occupant restraint system is activated by a separate drive device.

With the above configuration, the sensor weight 4 elastically supported by the spring member 2 is provided with air fluid resistance by the disc 11 that is displaced integrally with the sensor weight 4, thereby improving the vehicle performance. It is possible to set the operating characteristics of the switch so that only the sensitivity to deceleration in a specific region at the time of a collision becomes acute.

Normally, the sensor weight 4 is always affected by inertia due to the movement of the vehicle, and is constantly displaced within a range that does not close the contact made of the protrusion 5 and the lead piece 22. Therefore, if the spring member 2 becomes fatigued and breaks due to the influence of vibration, the holding force of the sensor weight decreases, and the operating characteristics of the switch may change. Therefore, in the present invention, electrical conduction at both ends of the spring member 2 is monitored so that a defective switch can be discovered at an early stage.

3 and 4 are views corresponding to FIGS. 1 and 2 showing a second embodiment based on the present invention, and the same parts as in the first embodiment are given the same reference numerals. A detailed explanation thereof will be omitted.

In this embodiment, a pair of notches 35b, 36b
A pair of spiral arms 35, 36 separated from each other by
A tongue piece 35a serving as an electrode terminal is provided only on one side. A resistor 28 is embedded in the front half 1b, and one of a pair of lead wires 29 extending from both ends of the resistor 28 is connected to the base end of the other spiral arm 36, and the other is connected to the lead piece 22. It is fixed to the swingable free end portion 22b of.

According to this embodiment, the terminal portion 20a and the tongue piece 35a
Between the lead piece 22, the lead wire 29, and the resistor 2
8. A minute current flows through the spiral springs 35 and 36, and the terminal portion 20a and the tongue piece 3
By forming a monitor circuit similar to that in the first embodiment between the lead piece 5a and the lead piece 22, it becomes possible to simultaneously monitor the conduction of the lead piece 22 and the breakage of the spring member 2.

<Effects of the invention> As described above, according to the invention, the state of the spring means that elastically supports the sensor weight can be easily monitored with an extremely simple structure, which further improves the reliability of the acceleration detection switch. , the effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is an overall vertical sectional view showing a first embodiment of an acceleration detection switch based on the present invention. Second
The figure is an end view taken along the - line in FIG. 1. FIG. 3 is a diagram corresponding to FIG. 1 showing a second embodiment of the acceleration detection switch based on the present invention. FIG. 4 is an end view taken along the - line in FIG. 3. 1... Casing, 1a... Rear half, 1b...
...Front half, 2... Spring member, 4... Sensor weight, 5... Protrusion, 6... Guide rod, 7...
Guide hole, 11...disc, 11a...projection, 12
... Backup plate, 13 ... Adsorption plate, 1
3a... Peripheral portion, 14... Retainer plate, 1
7... Opening, 19a, 19b... Push screw, 20
...Terminal board, 20a...Terminal section, 20b...
...retainer part, 21 ... hole, 22 ... lead piece,
22a... fixed point, 22b... free end, 24...
Foamed material, 25, 26... spiral arms, 25a, 26a
... tongue piece, 25b, 26b ... notch, 28 ... resistance, 29 ... lead wire, 35, 36 ... spiral arm,
35a... tongue piece, 35b, 36b... notch.

Claims (1)

[Claims for Utility Model Registration] (1) A sensor weight floatingly supported via spring means so as to be able to be displaced along a predetermined axis by inertia is displaced in the axial direction by the action of a predetermined acceleration. An acceleration detection switch configured to generate a signal, characterized in that means for detecting conduction of the spring means is connected to both ends of the spring means. (2) The acceleration according to claim 1 of the utility model registration claim, wherein the spring means is made of a plate spring material having a pair of spiral arms, and supports the sensor weight at the center thereof. Detection switch.